There are many situations where it is desirable to perform a composition analysis of a material and test procedures for determining the composition of a material may require several processing steps where the reagent used in one step must be thoroughly removed from the container before advancing to the next step of the test. For example, it may be desired to find the total fat content (also referred to as the Oil B content) of a foodstuff. An established conventional laboratory technique (ISO 6492:1999) for doing this is to place a known weight of a food or foodstuff into a cellulose thimble. The food or foodstuff may then be treated with a solvent under reflux conditions in order to remove the unbound fat therein and collected in a pre-dried and weighed receptacle.
The next step in the process is to release bound fat from the material. This is achieved using a process wherein the solvent-treated material is quantitatively transferred to a flask and gently boiled with an acid of known concentration for a period of 60 minutes under reflux conditions, cooled to ambient temperature and a filtration aid added and mixed.
The contents of the flask are quantitatively transferred and filtered through double moistened filter papers of a pre-determined porosity and washed with distilled water until all the acid is removed. The residue remaining is oven dried for a period of 4 hours, removed from the oven, cooled and quantitatively returned to the thimble.
The next step in the process is to remove the unbound fat from the residue and this is achieved by subjecting the residue contained within the thimble to a second treatment with solvent under reflux conditions for a period of 5 hours, collecting the fat in a pre-dried and weighed receptacle.
The solvent is removed from the receptacle by evaporation, thus leaving the fat behind.
The receptacle containing the fat is dried and weighed in order to determine the total weight of fat removed from the two treatments with solvent under reflux conditions.
The above process is labor intensive and time-consuming, allowing only one test per flask to be performed. The act of transferring the residue from the thimble to the flask for hydrolysis may result in leaving some of the residue behind. During the transfer of the hydrolyzed residue during the filtration process, some of the fat may be left behind. Fat may also be left behind on the reflux vessel, resulting in the loss of wanted constituents.
As prior art, there may also be mentioned WO99/02959.